Transformer &amp; inductor unit for heating valve seats

ABSTRACT

An induction heating device for inductively heating the conical surface of a valve seat in an engine block for subsequent quench hardening including a fixed multi-turn transformer primary winding having a central opening and a carrier having both the secondary of the transformer and the inductor mounted thereon wherein the carrier is selectively shiftable between a first position with the inductor spaced away from the valve seat and a second position with the inductor magnetically coupled to the valve seat and with the secondary then within the primary.

United States Patent 1151 3,696,224 Lewis [45] Oct. 3, 1972 [54]TRANSFORMER & INDUCTOR UNIT 2,496,950 2/ 1950 Marcus et a1. ..2l9/ 10.73FOR HEATING VALVE SEATS 2,757,268 7/1956 Edwards ..2l9/ 10.79 X 9 2 764660 9/1956 Grenoble ..219/10.79 X 72 I t 1 wemwmh 3,472,991 10/1969Seulen et a1. ..219/10.79 [73] Assignee: Park-Ohio Industries Inc.,Cleve- FOREIGN PATENTS 0R APPLICATIONS and, 1,537,394 7/1968 France..219/10.79 22 Filed: June 9,1971 1 H h Primary ExaminerWil iam e a [21]Appl 15l496 Attorney-Meyer, Tilberry & Body [52] US. Cl. ..2l9/l0.57,219/10.79, 266/5 E, ABSTRACT 336/119 336/129 An induction heatin gdevice for 1nduct1ve1y heating 3; g g gg g the conical surface of avalve seat in an engine block 1 le 0 I are i for subsequent quenchhardening including a fixed multi-tum transformer primary winding havinga central opening and a carrier having both the secondary [56]References Cited of the transformer and the inductor mounted thereonUNITED STATES PATENTS whereinthe carrier is selectively shiftablebetween a first position w1th the inductor spaced away from the2,223,902 12/1940 Somes ..336/119 X valve Seat and a second positionwith the inductor 2,241,431 5/1941 Somes ..266/51 E magnetically coupledto h valve Seat and with the 2,256,873 9/ 1941 Somes ..266/5 E secondarythen within the primary 2,280,861 4/1942 Somes ..336/119 2,281,2974/1942 Somes ..336/1 19 X 3 Claims, 5 Drawing Figures PATENTEDncrs SHEET1 BF 2 FIG INVENTOR. JOHN C. LEWIS Me 74mm, 5 Bad,

ATTORNEYS P'A'TENTED 0:13 m2 SHEET 2 BF 2 INVENTOR. JOHN C. LEWISATTORNEYS TRANSFORMER & INDUCTOR UNIT FOR HEATING VALVE SEATS Thepresent invention relates to the art of induction heating and moreparticularly to a transformer and inductor unit for heating the valveseat of an engine block preparatory to quench hardening.

The invention is particularly applicable for inductively heating theconical surface of a valve seat in a gray cast iron engine block for aninternal combustion engine, and it will be described with particularreference thereto; however, it must be appreciated that the inventionhas much broader applications and may be used for inductively heatingmany cylindrical, conical and flat surfaces.

In recent time, considerable work has been devoted to induction heatingdevices for heating the conical surface of a valve seat in an engineblock preparatory to quench hardening thereof. Generally, an inductor ispositioned adjacent the cylindrical surface and energized by a highfrequency power source. This causes induction heating of the valve seatfor subsequent quench hardening. The inductor must be movable into andout of the valve seat for processing successive engine blocks. Thispresents a substantial difficulty in an induction heating installation.The inductor itself must be connected onto the secondary of atransformer used to couple the power source to the inductor. Because ofthe reciprocal movement of the inductor, it has been suggested to useflexible leads between the inductor and the secondary. Such flexibleleads cause power loss, and the possibility of damage to the leads isalso present. Also, such an arrangement requires flexible leads fordirecting coolant to the inductor. To overcome the disadvantages ofproviding flexible connections to the inductor itself, it has beensuggested to connect the inductor rigidly to the secondary of thetransformer and have the secondary and primary reciprocate as a unit.This then requires flexible connections between power source and theprimary winding of the transformer. Again, flexible cooling leads arealso required in this type of installation.

These and other disadvantages are completely overcome by the presentinvention wherein the primary winding of the transformer is fixedlymounted and the inductor is secured with respect to the secondary of thetransformer on a carrier that is reciprocally mounted within theprimary. In this manner, flexible connections are limited only to thecoolant lines for both the transformer secondary and the inductoritself. These lines can be made flexible with less difficulty thanconductor leads.

In accordance with the present invention, there is provided an inductionheating device for inductively heating the conical surface of a valveseat in an engine block for subsequent quench hardening which devicecomprises a fixed multi-turn primary winding having a central openingwith an axis generally perpendicular to the turns, a carrier havingfirst and second longitudinally spaced portions with a single turn sheettype secondary adjacent the first portion and a single turn inductoradjacent the second portion and leads electrically connecting thesecondary and the inductor, and means for selectively shifting thecarrier generally along the axis of the primary between a first positionwith the inductor substantially spaced from the valve seat a distancenot corresponding to the proper magnetic coupling distance and a secondposition with the inductor magnetically coupled to the valve seat at theproper distance and with the secondary within the primary windingwhereby energizing of the primary causes inductive heating of the valveseat. In this manner, the inductor may be moved away from the engineblock for insertion and removal of the engine block from the inductionheating station. Also, it is possible to move the inductor to change thespacing with the valve seat without moving the primary. Movement of theinductor carries with it the movement of the secondary so that thesecondary is then positioned adjacent the primary winding of thetransformer for proper energization of the inductor when the inductor ismoved into the proper position to create the proper gap between theinductor and the valve seat.

The primary object of the present invention is the provision of atransformer and inductor unit for induction heating of the valve seat ofan engine block preparatory to quench hardening, which unit simplifiesthe electrical and coolant connections for the total installation.

Another object of the present invention is the provision of atransformer and inductor unit for induction heating of the valve seat ofan engine block preparatory to quench hardening, which unit is easy toinstall and reduces the number of flexible connections in theinstallation.

These and other objects and advantages will become apparent from thefollowing description taken together with the accompanying drawings inwhich:

FIG. 1 is a schematic side elevational view illustrating the presentinvention;

,FIG. 2 is a partial cross-sectional view taken generally along line 22of FIG. 1;

FIG. 3 is a cross-sectional view taken generally along line 3-3 of FIG.1;

FIG. 4 is a cross-sectional view taken line 4-4 of FIG. 1; and,

FIG. 5 is a partial side elevational view illustrating, somewhatschematically, a second embodiment of the present invention.

Referring now to the drawings wherein the showings are for the purposeof illustrating preferred embodiments of the invention only and not forthe purpose of limiting same, FIG. 1 shows an engine block A having aplurality of spaced exhaust ports B with valve seats 10, lower rod bores12 and machined surfaces 14. A plurality of induction heating devices Care positioned with one device above each of the exhaust ports. Theseinduction heating devices operate somewhat in unison with independentvertical adjustment; however, they are substantially identical instructure and only one of these units or devices will be described indetail.

A plurality of relatively fixed multi-turn primaries 20, 22, 24 arepositioned directly above the exhaust ports B and are connected inseries by leads 30, 32 with an appropriate high frequency power source34. The primaries are formed from a hollow conductor, and coolant iscirculated therethrough by inlet 40 and outlet 42. The fixed primary 20used with the first of the induction heating devices C will be used inthe following description.

A carrier 50 includes an upper support plate 52 and a lower insulatedbody 54 and is mounted to be generally along reciprocated within anappropriate guide arrangement schematically disclosed as guide surfaces56, 58. A single sheet secondary 60 having a hollow'structure is securedonto one end of the carrier 50 and includes a ductor 80 secured onto theinsulated body 54 of carrier 50. Coolant is circulated throughsecondary, through leads 70, 72 and through inductor 80. A variety ofarrangements could be used for the coolant circulating arrangement;however, in accordance with the illustrated embodiment of the presentinvention, there is provided a coolant inlet 90 connected by a flexiblehose to a source of' coolant, not shown. A circumferentially extendingbaffle 92 and anaxially extending baffle 94 causes the coolant to flowthrough the secondary 60 in accordance with the arrows shown in FIGS. 1,2 and 3. Coolant then flows down through lead 70, around inductor 80 andup lead 72 into the secondary 60. Thereafter, the coolant passes thenagain through a different portion of the secondary, as shown by thearrows,.to the outlet 96 which is connected by a flexible lead to thenext induction heating unit or to an ap propriate sump.

Carrier 50 includes a lower hose 100 for supporting a locator tip 102which coacts with the bore 12 to locate the inductor 80 concentricallywith respect to the valve seat 10 when the carrier 50 is in its lowerposition. To reciprocate the carrier, there is provided appropriatemeans, illustrated as a double acting pneumatic cylinder 1 10 connectedonto support plate 52 by a rod 112. Of course, other arrangements couldbe used for moving the carrier 50 in a vertical direction with respectto the engine block A. For instance, it is possible to employ a threadedrod driven by a rotating nut. The movement can be between a positionspaced from the engine block to the proper heating position or from aposition with the inductor generally contacting the block to a back-offposition with the inductor in the proper heating position.

In accordance with one operation, a cylinder 110 is actuated to move thecarrier 50 into an upper position. In this manner, an engine block A canbe moved into proper position with the respective exhaust ports alignedwith each of the induction heating devices C. Thereafter, the cylinder110 moves the carrier 50 downwardly into the position shown in FIG. 1with the inductor 80 magnetically coupled with the valve seat 10. Thetip 102 locates the inductor 80 concentric with the valve seat. Downwardposition of the carrier can be controlled by a sensing device, aservomechanism or a fixed position. Also, the tip 102 could contact thesurface 14 for location. When the carrier is in the'ir'iward, activeposition, the power source 34 energizes the inductor to inductively heatthe valve seat for. subsequent quenching in a manner well known in theart. After this has been done, the carrier 50 isthen shifted into itsupper position for removal of the engine block and insertion of asubsequent engine block.

In accordance with another operation, the inductor carrier 50 can beshifted from any position which does not provide a proper coupling gapbetween the inductor and valve seat to a position where the proper gapis obtained. 1

Referring now .to FIG.- 5,, a modification of the present invention isillustratedln accordance with this modification, theprimary surroundsthe secondary 122, similar to the secondary 60, and the body 124 mountsinductor 126.; In this embodiment, the inductor 126 is only closelyspaced from the secondary 122. Leads 130, 132 are relatively short ascompared to the leads 70, 72 in the previously discussed embodiment ofthe present invention. Thus, the length of the carrier is substantiallyreduced. Coolant is introduced into the secondary through inlet 134 andis withdrawn from the secondary through outlet 136. The coolantarrangement through the secondary, the connecting leads and the inductoris substantially similar to the coolant system employed in the firstembodiment of theinvention.

By using the fixed primary, it is possible to employ different carrierswhen different types of valveseats are to be heated. Also, in someinstances it may be possible to employ a plurality of carriers on anindexing mechanism each of the carriers having a difierent type ofinductor and a similar secondary structure. With this type of system,when a given induction heating operation is to be performed, the propercarrier is indexed into position with the primary and then moveddownwardly through the primary into proper heating position.

Having thus defined my invention, I claim:

1. An induction heating device for inductively heating the conicalsurfaces of two adjacent valve seats in an engine component forsubsequent quench hardening, said device comprising: a heating unit foreach valve seat, each of said units having a fixed multi-turn primarywinding having a central opening with an axis generally perpendicular tosaid turns and a given axial length; a carrier having first and secondlongitudinally spaced portions, a single turn sheet type secondaryadjacent said first portion and having a central axis generallycoinciding with said axis of said primary winding, a single turninductor adjacent said second portion and having a central axisgenerally parallel with said axis of said primary, and leadselectrically connecting said secondary and said inductor; means forselectively shifting said carrier generally along said axis of saidprimary winding between a first positionand a second position with saidinductor magnetically coupled to the valve seat associated with saidunit at a desired spacing and with said secondary within said primarywinding whereby energizing of said .primary causes inductive heating ofsaid valve seat; and, said carrier including a third portion spaced fromsaid second portion on the side opposite to said first portion and alocator means fixed onto said third portion and movable with saidinductor, said locator means having an outwardly protruding nosecoacting with a bore in said component and concentric with said conicalsurface for centering said inductor with said valve seat surfaceassociated with said unit when said carrier is in said second portion.

2. An induction heating device as defined in claim 1 wherein saidsecondary includes a single turn winding having a generally cylindricalportion.

3. An induction heating device as defined in claim 1 wherein saidinductor'is only slightly spaced from said secondary.

1. An induction heating device for inductively heating the conicalsurfaces of two adjacent valve seats in an engine component forsubsequent quench hardening, said device comprising: a heating unit foreach valve seat, each of said units having a fixed multi-turn primarywinding having a central opening with an axis generally perpendicular tosaid turns and a given axial length; a carrier having first and secondlongitudinally spaced portions, a single turn sheet type secondaryadjacent said first portion and having a central axis generallycoinciding with said axis of said primary winding, a single turninductor adjacent said second portion and having a central axisgenerally parallel with said axis of said primary, and leadselectrically connecting said secondary and said inductor; means forselectively shifting said carrier generally along said axis of saidprimary winding between a first position and a second position with saidinductor magnetically coupled to the valve seat associated with saidunit at a desired spacing and with said secondary within said primarywinding whereby energizing of said primary causes inductive heating ofsaid valve seat; and, said carrier including a third portion spaced fromsaid second portion on the side opposite to said first portion and alocator means fixed onto said third portion and movable with saidinductor, said locator means having an outwardly protruding nosecoacting with a bore in said component and concentric with said conicalsurface for centering said inductor with said valve seat surfaceassociated with said unit when said carrier is in said second portion.2. An induction heating device as defined in claim 1 wherein saidsecondary includes a single turn winding having a generally cylindricalportion.
 3. An induction heating device as defined in claim 1 whereinsaid inductor is only slightly spaced from said secondary.